.TH iopending 1m  "$Date:: 2007-08-05 #$" "USER COMMANDS"
.SH NAME
iopending \- plot number of pending disk events. Uses DTrace.
.SH SYNOPSIS
.B iopending
[\-c] [\-d device] [\-f filename] [\-m mount_point] [interval [count]]
.SH DESCRIPTION
This samples the number of disk events that are pending and plots a
distribution graph. By doing this the
"serialness" or "parallelness" of disk behaviour can be distinguished.
A high occurance of a pending value of more than 1 is an indication of
saturation.

Since this uses DTrace, only the root user or users with the
dtrace_kernel privilege can run this command.
.SH OS
Solaris
.SH STABILITY
stable - needs the io provider.
.SH OPTIONS
.TP
\-c
clear screen
.TP
\-d device
instance name to snoop (eg, dad0)
.TP
\-f filename
full pathname of file to snoop
.TP
\-m mount_point
mountpoint for filesystem to snoop
.SH EXAMPLES
.TP
Default output, print I/O summary every 1 second,
# 
.B iopending
.PP
.TP
Print 10 second samples,
# 
.B iopending
10
.PP
.TP
Print 12 x 5 second samples,
#
.B iopending
5 12
.PP
.TP
Snoop events on the root filesystem only,
#
.B iopending
\-m /
.PP
.SH FIELDS
.TP
value
number of pending events, 0 == idle
.TP
count
number of samples @ 1000 Hz
.TP
load
1 min load average
.TP
disk_r
total disk read Kb for sample
.TP
disk_w
total disk write Kb for sample
.PP
.SH IDEA
Dr Rex di Bona
.PP
.SH DOCUMENTATION
See the DTraceToolkit for further documentation under the 
Docs directory. The DTraceToolkit docs may include full worked
examples with verbose descriptions explaining the output.
.SH EXIT
iopending will run forever until Ctrl\-C is hit, or the
specified count is reached.
.SH AUTHOR
Brendan Gregg
[Sydney, Australia]
.SH SEE ALSO
iosnoop(1M), iotop(1M), dtrace(1M)

